1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device. In particular, the present invention relates to a manufacturing method of a semiconductor device capable of exchanging data with wireless communication.
2. Description of the Related Art
In recent years, a semiconductor device capable of exchanging data with wireless communication has been actively developed. Such a semiconductor device is called an IC tag, an ID tag, an RF (Radio Frequency) tag, an RFID (Radio Frequency Identification) tag, a wireless tag, an electronic tag, a wireless processor, a wireless memory, a wireless chip, or the like.
Wireless chips which have been put into practical use mainly use a silicon substrate (wafer). In addition, manufacturing of a thin wireless chip by using a technology (referred to as a “backgrind technology”) of grinding and polishing a surface (a reverse side) of a silicon substrate has been recently studied. It is known that the backgrind technology causes a crack or a grinding mark (e.g., Reference 1: Japanese Published Patent Application No. 2004-282050).
For thinning a wireless chip to the utmost, it is necessary to grind and polish a substrate as much as possible. However, if the substrate with a thickness smaller than a certain thickness is polished, strength of the substrate cannot be maintained, which may result in destruction of the substrate itself and eventually of an element formed over the substrate.